Genetic screening of patients with medullary thyroid cancer in a referral center in Greece during the past two decades.

OBJECTIVE: Mutations in the RET gene are responsible for hereditary medullary thyroid cancer (MTC) and may vary between ethnic groups. We report the spectrum of mutations detected in patients with MTC in a referral center in Greece. PATIENTS AND METHODS: Screening for RET mutations was performed in 313 subjects from 188 unrelated families: 51 patients had clinical suspicion for familial disease, 133 were apparently sporadic, four patients had only C cell hyperplasia, and 125 were family members. Exons 8, 10, 11, and 13-16 were screened. RESULTS: A total of 58 individuals (30.85%) were RET mutations carriers, 120 (63.8%) were finally classified as sporadic, 13 apparently sporadic cases (9.8%) were identified with RET mutation: ten carried the exon 8 at codon 533 mutation (previously reported), two the exon 14 at codon 804 mutation, and one the exon 13 at codon 768 mutation. Six patients (3.19%) with clinical features of multiple endocrine neoplasia type 2A and negative for RET mutations were classified as 'unknown cause'. The mutations of hereditary cases were as follows: 21 cases (36.2%) in exon 8 codon 533, 19 (32.8%) in exon 11 codon 634, nine (15.5%) in exon 10, five (8.6%) in exon 16, three (5.2%) in exon 14 codon 804, and one in exon 13 codon 768 (1.7%). CONCLUSION: The spectrum of RET mutations in Greece differs from that in other populations and the prevalence of familial cases is higher. The exon 8 (Gly533Cys) mutation was the most prevalent in familial cases unlike other series, followed by exon 11 (codon 634) mutations which are the most frequent elsewhere. The wide application of genetic screening in MTC reveals new molecular defects and helps to characterize the spectrum of mutations in each ethnic group.

High prevalence of exon 8 G533C mutation in apparently sporadic medullary thyroid carcinoma in Greece.

OBJECTIVE: Genetic screening for ret mutation has become routine practice in the evaluation of medullary thyroid carcinoma (MTC). Approximately 25% of these tumours are familial, and they occur as components of the multiple endocrine neoplasia type 2 syndromes (MEN 2A and 2B) or familial MTC. In familial cases, the majority of mutations are found in exons 10, 11, 13, 14 or 15 of the ret gene. A rare mutation involving exon 8 (G533C) has recently been reported in familial cases of MTC in Brazil and Greece; some of these cases were originally thought to be sporadic. The aim of this study was to re-evaluate a series of sporadic cases of MTC, with negative family history, and screen them for germline mutations in exon 8. DESIGN AND PATIENTS: Genomic DNA was extracted from peripheral lymphocytes in 129 unrelated individuals who had previously been characterized as 'sporadic' based on the negative family history and negative screening for ret gene mutations. Samples were analysed in Applied Biosystems 7500 real-time PCR and confirmed by sequencing. MEASUREMENTS AND RESULTS: The G533C exon 8 mutation was identified in 10 of 129 patients with sporadic MTC. Asymptomatic gene carriers were subsequently identified in other family members. CONCLUSION: In our study, we found that 7·75% patients with apparently sporadic MTC do carry G533C mutation involving exon 8 of ret. We feel that there is now a need to include exon 8 mutation screening in all patients diagnosed as sporadic MTC, in Greece.

Severity of cardiovascular disease in postmenopausal women: associations with common estrogen receptor alpha polymorphic variants.

OBJECTIVE: Impaired estrogen action is a risk factor for coronary artery disease (CAD). Associations of CAD with estrogen receptor alpha (ER alpha) polymorphisms, which may influence sensitivity to estrogen, have been reported for men; the data concerning women are not conclusive. We investigated the association of common ER alpha polymorphisms with the severity of CAD and with metabolic and reproductive factors in postmenopausal women undergoing coronary angiography. METHODS: ER alpha polymorphisms at positions c.454-397 T>C (PvuII) and c.454-351 A>G (XbaI) were studied in 157 women (age 45-88 years). The severity of CAD was assessed by the number of arteries with >50% stenosis in the angiography. RESULTS: There was a significant association between the TT, TC, and CC genotypes (PvuII) and the severity of CAD (P=0.008); similar results were obtained for the XbaI polymorphism (P=0.021). These associations were independent of other risk factors for CAD. Women homozygous for the C allele had significantly higher triglyceride and insulin levels; they belonged more frequently to the group with a low number of births (n

The androgen receptor gene CAG polymorphism is associated with the severity of coronary artery disease in men.

OBJECTIVE: The role of androgens in the pathogenesis of coronary artery disease (CAD) remains controversial. The length of the polyglutamine stretch of the transactivation domain (CAG repeat) of the androgen receptor (AR) inversely affects androgen activity. The aim of this study was to investigate the effect of this polymorphism of the AR gene in the extent of CAD in male patients. DESIGN AND PATIENTS: The relationship of the length of the AR gene CAG repeat on the severity of CAD was examined in 131 men (36-86 years old) undergoing coronary angiography. MEASUREMENTS: The severity of CAD was assessed by the number (0-3) of coronary vessels with > 50% reduction in the luminal diameter. The interaction of the AR gene polymorphism with the intima media thickness (IMT) of peripheral arteries and serum levels of sex steroids, insulin and biochemical parameters were also studied. RESULTS: The upper quartile of CAG length (range 9-30) was > or = 23 repeats (longAR). The mean body mass index (BMI) of patients with shorter repeats (< 23; shortAR) was significantly lower than in men with longAR (26.1 vs. 27.6, respectively; P = 0.043 M-W Rank test). There was no correlation between the AR gene repeat length and serum testosterone. Oestradiol levels were significantly higher in longAR (0.19 +/- 0.08 nmol/l vs. 0.14 +/- 0.07 in shortAR, P = 0.031). This difference was independent of BMI. Men with shortAR had significant CAD (i.e. one to three arteries with stenosis) more frequently (79.5%) than men with longAR (20.5%); of the subjects with stenosis in no arteries, 56.5% had shortAR and 43.5% longAR (chi2 = 4.3, P = 0.038). This association was independent of age and BMI. The IMT of peripheral arteries, lipid parameters, basal insulin resistance, blood pressure and family history for early CAD, did not differ according to AR length. CONCLUSIONS: The shorter CAG repeat of the AR gene is associated with more severe CAD, which suggests a role for the sensitivity to androgens in the increased frequency of CAD in males. In addition, a protective role of endogenous oestrogen, which is higher in the longAR subgroup, can contribute to the observed difference.